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Angewandte Chemie (International Ed. in... Jun 2024Structural adhesives that do not require heating are in high demand in the automotive and electronics industries. However, it remains a challenge to develop robust...
Structural adhesives that do not require heating are in high demand in the automotive and electronics industries. However, it remains a challenge to develop robust adhesives that rapidly achieve super adhesion near ambient temperature. Herein, a room-temperature curable, fast-bonding, and super strong epoxy-based structural adhesive was designed from the perspective of cross-scale structure, which lies in threefold pivotal aspects: (i) high branching topology of glycerol carbonate-capped polyurethane (PUGC) increases the kinetics of the ring-opening reaction, contributing to fast crosslinking and the formation of abundant urethane and hydroxyl moieties; (ii) asynchronous crosslinking of epoxy and PUGC synergistically induces phase separation of PUGC within the epoxy resin and the resulting PUGC domains surrounded by interpenetrated shell serves to efficiently toughen the matrix; (iii) abundant dynamic hydrogen bonds including urethane and hydroxyl moieties, along with the elastomeric PUGC domains, dissipate energy of shearing force. As a result, the adhesive strength rapidly grows to 16 MPa within 4 hours, leveling off to 21 MPa after 7 hours, substantially outperforming commercial room-temperature curable epoxy adhesives. The results of this study could advance the field of high-performance adhesives and provide valuable insights into designing materials for efficient curing at room temperature.
PubMed: 38927000
DOI: 10.1002/anie.202408840 -
Advanced Science (Weinheim,... Jun 2024Tremendous popularity is observed for multifunctional flexible electronics with appealing applications in intelligent electronic skins, human-machine interfaces, and...
Tremendous popularity is observed for multifunctional flexible electronics with appealing applications in intelligent electronic skins, human-machine interfaces, and healthcare sensing. However, the reported sensing electronics, mostly can hardly provide ultrasensitive sensing sensitivity, wider sensing range, and robust cycling stability simultaneously, and are limited of efficient heat conduction out from the contacted skin interface after wearing flexible electronics on human skin to satisfy thermal comfort of human skin. Inspired from the ultrasensitive tactile perception microstructure (epidermis/spinosum/signal transmission) of human skin, a flexible comfortably wearable ultrasensitive electronics is hereby prepared from thermal conductive boron nitride nanosheets-incorporated polyurethane elastomer matrix with MXene nanosheets-coated surface microdomes as epidermis/spinosum layers assembled with interdigitated electrode as sensing signal transmission layer. It demonstrates appealing sensing performance with ultrasensitive sensitivity (≈288.95 kPa), up to 300 kPa sensing range, and up to 20 000 sensing cycles from obvious contact area variation between microdome microstructures and the contact electrode under external compression. Furthermore, the bioinspired electronics present advanced thermal management by timely efficient thermal dissipation out from the contacted skin surface to meet human skin thermal comfort with the incorporated thermal conductive boron nitride nanosheets. Thus, it is vitally promising in wearable artificial electronic skins, intelligent human-interactive sensing, and personal health management.
PubMed: 38924313
DOI: 10.1002/advs.202401800 -
Cureus May 2024Several approaches have been suggested for implant removal. However, further research is necessary to review data regarding the amount of bone removed and the duration...
PURPOSE
Several approaches have been suggested for implant removal. However, further research is necessary to review data regarding the amount of bone removed and the duration of removal time for different procedures. This study evaluates and compares various implant removal techniques. Materials and methods: A polyurethane block was scanned to create an implant surgical guide. Afterward, implant-guided surgery was performed on 60 simulated bone blocks. The implants were then separated into four groups and removed utilizing the counter-torque ratchet, trephine drills, burs, and piezosurgery.
RESULTS
For the weight of bone loss, there were significant differences in the median between the counter-torque ratchet technique (CTRT) and trephine (p < 0.01), CTRT and bur (p < 0.01), trephine and piezo (p < 0.01), and bur and piezo (p = 0.04). All groups, except CTRT and the piezo group, demonstrated a statistically significant difference (p < 0.01) in the procedure durations. Regarding the volume of bone loss, a statistically significant difference (p < 0.01) was found between each group. Conclusions: CTRT showed the least amount of bone loss. On the other hand, the trephine technique was demonstrated to be the fastest. It is essential to consider the limitations and risks when choosing the approach for implant removal.
PubMed: 38919230
DOI: 10.7759/cureus.61104 -
ACS Nano Jun 2024Elastic electromagnetic fibers are promising building blocks for next-generation flexible electronics. However, fabrication of elastic fibers is still difficult and...
Elastic electromagnetic fibers are promising building blocks for next-generation flexible electronics. However, fabrication of elastic fibers is still difficult and usually requires organic solvents or high temperatures, restricting their widespread applications. Furthermore, the continuous production of electromagnetic fibers has not been realized previously. In this study, we propose an ionic chelation strategy to continuously produce electromagnetic fibers with a magnetic liquid metal (MLM) as the core and elastic polyurethane as the sheath in water at room temperature. Sodium alginate (SA) has been introduced to rapidly chelate with calcium ions (Ca) in a coagulation bath to support the continuous spinning of waterborne polyurethane (WPU) as a sheath. Meanwhile, WPU-encapsulated MLM microparticles efficiently suppress the fluid instability of MLM for continuous extrusion as the core. The resultant fiber exhibits excellent mechanical performances (tensile strength and toughness up to 32 MPa and 124 MJ/m, respectively), high conductive stability in large deformations (high conductivity of 7.6 × 10 S/m at 580% strain), and magnetoactive properties. The applications of this electromagnetic fiber have been demonstrated by conductance-stable wires, sensors, actuation, and electromagnetic interference shielding. This work offers a water-based molecular principle for efficient and green fabrication of multifunctional fibers and will inspire a series of applications.
PubMed: 38916583
DOI: 10.1021/acsnano.4c04455 -
RSC Advances Jun 2024Advances in high-efficiency solar cells introduce photon management challenges, including the difficult texturization of flat surfaces and low photon utilization at...
Advances in high-efficiency solar cells introduce photon management challenges, including the difficult texturization of flat surfaces and low photon utilization at short wavelengths. While bifacial crystalline silicon solar cells have a front pyramid structure and SiN layers reduce reflections, managing photons on the flat backside remains a challenge. To enhance light utilization, a soft nanoimprint technique was utilized to create pyramid micro-structured polyurethane films doped with europium (Eu) complex. These films, which possess anti-reflection and down-conversion properties, can be applied externally to various high-efficiency solar cells without compromising electrical performance. Research on the backside of bifacial PERC solar cells revealed that the optimal composite functional film increases the integrated current by 5.70%, with a 1.27% gain from down-conversion effects. This specialized film presents a novel approach to interface matching for different types of solar cells.
PubMed: 38915332
DOI: 10.1039/d4ra03397c -
Journal of Materials Chemistry. B Jun 2024Postoperative adhesions, a prevalent complication following abdominal surgery, affect 90% of patients undergoing abdominal surgical procedures. Currently, the primary...
Postoperative adhesions, a prevalent complication following abdominal surgery, affect 90% of patients undergoing abdominal surgical procedures. Currently, the primary approach to prevent postoperative adhesions involves physical isolation of the surgical site and surrounding tissues using a hydrogel; however, this method represents a rudimentary strategy. Herein, considering the impact of oxidative stress and free radicals on postoperative adhesion during wound healing, an injectable antioxidant hydrogel, named PU-OHA-D, was successfully synthesized, which is formed by the crosslinking of dopamine-modified oxidized hyaluronic acid (OHA-D) and dihydrazide-terminated polyurethane (PU-ADH) through hydrazone bonding. PU-OHA-D hydrogel possesses versatile characteristics such as rapid gel formation, injectability, self-repair capability and biodegradability. Additionally, they exhibit an excellent ability to clear free radicals and superior tissue adhesion. PU-OHA-D can be injected to form a hydrogel to prevent abdominal wall-cecum adhesion. Importantly, it can effectively eliminate free radicals and inhibit oxidative stress at the wound site. Thereby, it leads to collagen physiological degradation and prevents the occurrence of postoperative adhesions. The bioinspired hydrogel demonstrates its great potential in preventing postoperative adhesion and promoting wound healing.
PubMed: 38915270
DOI: 10.1039/d4tb00805g -
ACS Applied Materials & Interfaces Jun 2024Developing fabric-based strain sensors with high sensitivity and stability is in high demand for wearable electronics. Herein, carbon nanotubes (CNTs) and polypyrrole...
Developing fabric-based strain sensors with high sensitivity and stability is in high demand for wearable electronics. Herein, carbon nanotubes (CNTs) and polypyrrole (PPy) are coated on a thermoplastic polyurethane (TPU) fabric as strain sensors. A microbridge structure, in which CNT bridges the stretching-induced cracks, has been designed for the TPU-CNT-PPy strain sensor. The microbridge structure can significantly enhance the electrical resilience, ensuring the improved sensitivity and stability of strain sensors. As a result, our TPU-CNT-PPy strain sensors deliver high sensitivity (GF = 231.5) with a broad working range (150%) and fast response and recovery time (166/195 ms). In addition, our TPU-CNT-PPy could also be used as flexible electrodes of the microsupercapacitors (MSCs) as a power supplier for the integrated sensing system. The TPU-CNT-PPy-based MSCs exhibit a high specific capacitance (460.3 mF cm at 0.5 mA cm) and excellent cycling stability (96.69% capacitance retention for 10,000 charge/discharge cycles). Finally, we demonstrated an integrated sensing system using TPU-CNT-PPy as both MSCs and strain sensors, where the current signals of the sensors could be well detected via Bluetooth. This study offers a microbridge strategy to fabricate strain sensors with high sensitivity and stability and develops an integrated sensing system for the actual applications of wearable electronics.
PubMed: 38914520
DOI: 10.1021/acsami.4c05753 -
Materials Horizons Jun 2024It is challenging for ionic liquid gels to achieve the combination of rapid self-healing with high toughness. Here, ionic liquid gels (DI-PR) were prepared from readily...
It is challenging for ionic liquid gels to achieve the combination of rapid self-healing with high toughness. Here, ionic liquid gels (DI-PR) were prepared from readily available materials. A dynamic covalently bonded oxime-carbamate was prepared from polycaprolactone diol, isophorone diisocyanate and dimethylethyleneglyoxime, followed by addition of the "rigid-flexible" cross-linking agent rutin to chemically cross-link the polymer chains and afford the ionic liquid gels, DI-PR. The tensile strength, elongation at break and toughness of the DI-PR gels were as high as 16.5 MPa, 1132.6%, and 52.6 MJ m, respectively. The toughness is similar to that of natural silkworm silk (70 MJ m) and wool (60 MJ m). After stretching, the DI-PR can rebound within 1 s, their room temperature self-healing rate is as high as 92%, they remain functional over the temperature range -50 °C to 140 °C and the interface with a steel plate has an adhesion toughness of >2000 J m. These properties mean that the DI-PR gels are particularly suitable for use as anticorrosion coatings for submarine and underground gas and oil pipelines. The use of rutin, which combines rigid quercetin-based structural units with flexible glycoside-based structural units, as a cross-linking agent, provides a new method for improving the toughness of soft materials through its synergistic interaction with hard and soft chain fragments of polyurethanes.
PubMed: 38910542
DOI: 10.1039/d4mh00497c -
Journal of Zhejiang University.... Jun 2024Artificial vascular graft (AVG) fistula is widely used for hemodialysis treatment in patients with renal failure. However, it has poor elasticity and compliance, leading...
Artificial vascular graft (AVG) fistula is widely used for hemodialysis treatment in patients with renal failure. However, it has poor elasticity and compliance, leading to stenosis and thrombosis. The ideal artificial blood vessel for dialysis should replicate the structure and components of a real artery, which is primarily maintained by collagen in the extracellular matrix (ECM) of arterial cells. Studies have revealed that in hepatitis B virus (HBV)-induced liver fibrosis, hepatic stellate cells (HSCs) become hyperactive and produce excessive ECM fibers. Furthermore, mechanical stimulation can encourage ECM secretion and remodeling of a fiber structure. Based on the above factors, we transfected HSCs with the hepatitis B viral X () gene for simulating the process of HBV infection. Subsequently, these -HSCs were implanted into a polycaprolactone-polyurethane (PCL-PU) bilayer scaffold in which the inner layer is dense and the outer layer consists of pores, which was mechanically stimulated to promote the secretion of collagen nanofiber from the -HSCs and to facilitate crosslinking with the scaffold. We obtained an ECM-PCL-PU composite bionic blood vessel that could act as access for dialysis after decellularization. Then, the vessel scaffold was implanted into a rabbit's neck arteriovenous fistula model. It exhibited strong tensile strength and smooth blood flow and formed autologous blood vessels in the rabbit's body. Our study demonstrates the use of human cells to create biomimetic dialysis blood vessels, providing a novel approach for creating clinical vascular access for dialysis.
Topics: Rabbits; Animals; Hepatic Stellate Cells; Renal Dialysis; Polyesters; Viral Regulatory and Accessory Proteins; Tissue Scaffolds; Transfection; Bionics; Polyurethanes; Blood Vessel Prosthesis; Extracellular Matrix; Humans; Hepatitis B virus; Collagen; Tissue Engineering; Trans-Activators
PubMed: 38910495
DOI: 10.1631/jzus.B2300479 -
Journal of Chromatography. A Jun 2024In this research, electrospun nanofibers based on copper-based metal organic framework (MOF)/polyurethane (PU) were prepared in order to achieve an applicable and...
In this research, electrospun nanofibers based on copper-based metal organic framework (MOF)/polyurethane (PU) were prepared in order to achieve an applicable and superior extractive phase. The incorporation of MOF, in the synthesized nanocomposite contributed to the enhanced sorption efficiency. The prepared sorbent was implemented for the thin film microextraction (TFME) of target compounds with subsequent quantification using gas chromatography-mass spectrometry (GC-MS). To obtain the maximum efficiency of the synthesized sorbent, the influential parameters on extraction and desorption steps, including the MOF percentage in nanocomposite, desorption solvent type and its volume, desorption time, solution ionic strength and extraction time were optimized. After method development, the linear dynamic range (0.02-700 μg L), limits of detection (LODs) (0.005-0.1 μg L) and limits of quantification (LOQs))0.02-0.33 μg L(were calculated. The relative standard deviations values for intra-day and inter-day analysis were found to be in the range of 4.3-5.3 % and 6.2-8.1 %, respectively. The developed method was validated for the TFME of model organochlorine (OC) pesticide residues in fish, soil and water samples. the recovery values for the spiked samples at two concentration levels of 5 and 100 µg l were found in the range of 72-110 %.
PubMed: 38909520
DOI: 10.1016/j.chroma.2024.465061